Pennsylvania measles outbreak hits 1,078 cases, biggest in the US in 35 years

Pennsylvania is now the center of the worst measles outbreak in the United States in 35 years.

The state Department of Health reported Wednesday that 145 new cases were confirmed in the past week, bringing the total to 1,078. Five residents have died. Another 207 have been hospitalized. A third of the cases are in people under 18, and less than 1 percent of those infected were fully vaccinated. Lancaster County is the hardest hit, with 401 cases.

The outbreak has now surpassed South Carolina's outbreak of 997 cases as the largest in the country in a generation. Nationally the picture is grim: 3,887 measles cases have been recorded across the US as of October 1, with 40 separate outbreaks this year compared with 16 in all of 2024. All of 2025 saw 2,289 cases. The CDC has confirmed two measles related deaths nationally this year without naming the states.

Measles was declared eliminated in the United States in 2000. The MMR vaccine is about 97 percent effective after two doses, which makes the vaccination profile of this outbreak, fewer than 1 in 100 cases fully vaccinated, the story in a single number. A disease America buried 26 years ago is back at a scale not seen in a generation, and it is finding the unvaccinated.